| 摘要 |
PROBLEM TO BE SOLVED: To reduce the range in which a control gain must change, and in addition, to prevent speed resolution from becoming roughened at high-speed control. SOLUTION: In a speed difference detecting circuit 9, which detects the driving state of an ultrasonic motor at prescribed operating timing upon receiving the output of an encoder 8 which outputs the signal corresponding to the drive state of the motor 7, the operating timing is changed according to the target drive state of the motor 7. A speed control circuit 4 decides the drive condition of the motor 7 so that the operating state turns into a target state upon receiving speed difference information from the speed difference detecting circuit 9. A pulse generating circuit 5 and a boosting circuit 6 generate the drive AC signal, corresponding to the drive condition decided by means of the control circuit 4 and output the signal to the motor 7. |
